A histomorphometric comparison of bone in young growing rats fed an elemental diet versus a chemically defined...

This study was designed to examine whether a synthetic elemental diet, which could be adapted for total parenteral nutrition, is capable of promoting bone growth comparable to a commercially available liquid polymeric diet. The orally fed young rat was chosen as a model of rapid bone growth. Sixteen male, Wag/Rij rats weighing 120 +/- 3 g were divided into two groups of eight rats each. One group was fed an elemental diet formulated to approximate the nutritional requirements of the rat as recommended by the National Research Council. The comparison group received a liquid polymeric diet. After 14 days there were no significant differences between groups in femur and tibia weights, cortical and medullary area, periosteal and endosteal label area, growth plate width, percent cancellous bone, bone apposition rates and osteoblasts and osteoclasts per millimeter. Both groups maintained a positive calcium and nitrogen balance. These data indicate that bone growth, structure and remodeling comparable to that seen in a polymeric-fed comparison group can be achieved in young rats when fed an oral dextrose/amino acid-based elemental solution for 2 weeks.